Science China Materials最新文献

High-entropy alloys (HEAs) have shown great promise in the CO₂ reduction reaction (CO₂RR) due to their tunable composition and unique physical and chemical properties. However, the role of HEAs in CO₂RR and the underlying reaction mechanism remain underexplored, particularly through in situ techniques. In this work, we investigate the mechanism of CO₂ reduction on AuAgCuPdPt HEAs using in situ Raman spectroscopy and attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy to reveal key intermediates and reaction pathways. Our results demonstrate that within the potential window of −0.2 to −0.7 V vs. reversible hydrogen electrode (RHE), the AuAgCuPdPt HEAs efficiently reduce CO₂ to CO, achieving a Faradaic efficiency (FE) for CO greater than 90%, with a peak FE of 96.5% at −0.3 V vs. RHE. The CO₂⁻ intermediate was observed at low potentials, revealing the reaction pathway in the CO₂ reduction process. Additionally, in situ ATR-FTIR results suggest that the introduction of an appropriate amount of Pt metal not only promotes water dissociation to generate protonic hydrogen, but also facilitates the desorption of *CO intermediates. The kinetic isotope effect of hydrogen-deuterium (H-D) confirms that water dissociation acts as a key proton donor in CO₂RR. Furthermore, the catalyst of AuAgCuPdPt HEAs was applied as cathodes in a Zn-CO₂ battery, achieving 90.23% FE for CO and a power density of 3.474 mW cm⁻². This study provides new insights into the mechanistic understanding of CO₂ reduction and underscores the importance of in situ spectroscopic techniques for advancing the design of efficient electrocatalysts for CO₂ conversion.

Perovskite quantum dots (PQDs) hold great potential for brain-like neuromorphic computing. However, the development of PQDs-based synaptic devices is hindered by interfacial defects and limited stability. Here, we demonstrate a high-performance Cs₂AgBiBr₆ QDs/organic single crystal heterojunction synaptic device, fabricated via a novel space-confined vertical growth technique combined with a polymer-free transfer process. Vertically grown organic single crystals enable superior carrier mobility and facilitate the formation of low-defect interfaces with PQDs. The heterojunction exhibits remarkable photosensitivity (7.22 × 10⁵ at 425 nm) and detectivity (2.15 × 10¹⁵ Jones), owing to the strong optical absorption of PQDs coupled with the superior charge transport characteristics of organic single crystals. Notably, the device achieves dual-functional light adaptation, emulating synaptic behaviour under blue light while exhibiting photo-switching under green/red light. This unique capability enables smart blue-light hazard protection. This work not only provides a versatile platform for high-performance PQDs-based synaptic devices but also advances the development of brain-inspired neuromorphic systems for next-generation computing and intelligent sensing.

Nickel oxide (NiO_x) is widely used as a hole transport material in inverted perovskite solar cells. However, its practical application is limited by its low intrinsic conductivity and insufficient hole extraction ability, which leads to significant interfacial defect formation that reduces device efficiency and stability. To overcome these issues, small organic molecules (2,6-NOT and 1,5-NOT) have been developed and introduced to modify NiO_x. The two molecules are isomers that share the same structure but differ in the substitution positions of the functional groups. The experimental results show that, compared with 2,6-NOT, 1,5-NOT, featuring extended conjugation, more effectively enhances the hole extraction/transport capabilities and conductivity of NiO_x. The NiO_x/1,5-NOT-based device achieves a remarkable power conversion efficiency of 24.20%, along with excellent long-term stability, surpassing those of the NiO_x control device (18.12%) and the 2,6-NOT-based device (21.87%). These findings demonstrate that modifying NiO_x with small organic molecules can significantly improve the charge transport performance and that increasing the molecular planarity is particularly beneficial for enhancing hole transport and reducing the number of defects, thereby increasing both the efficiency and stability. These results provide a new strategy for NiO_x modification via small organic molecules.

Metal sulfides like CdS hold promise for solar-driven H₂O₂ productions but suffer from rapid charge recombination and severe photocorrosion. This study introduces a dual-functional strategy synergizing sulfur vacancy (S_v) engineering and polydopamine (PDA) coating to overcome these limitations. S_v-CdS nanorods were hydrothermally synthesized with tunable vacancy concentrations, followed by in-situ PDA deposition to construct a direct Z-scheme heterojunction. X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculations reveal that the introduction of S vacancies reduces the work function of CdS, facilitating energy level alignment with PDA and enabling efficient electron transfer from CdS to PDA. By tuning the concentration of S vacancies, the charge transfer efficiency can be maximized. As a result, the photocatalytic H₂O₂ production rate reaches 2539.5 µmol g⁻¹ h⁻¹ under visible light, and further increases to 4395.5 µmol g⁻¹ h⁻¹ after PDA encapsulation —15.6 times higher than that of pristine CdS. Concurrently, PDA enhances O₂ adsorption and protects S_v-CdS from photocorrosion. S_v-CdS@PDA exhibited superior photostability compared to S_v-CdS after three consecutive photocatalytic cycles. Mechanistic studies suggest that the Z-scheme heterojunction effectively separates electron-hole pairs: electrons in the conduction band of CdS reduce O₂ to ·O₂⁻, which is subsequently converted to H₂O₂, while holes in the valence band of S_v-CdS oxidize water to replenish O₂. This work provides fundamental insights into engineering charge transfer and stability in sulfide-based photocatalysts.

Solid-state lithium batteries are promising next-generation energy storage systems due to their high safety and energy density. However, the poor low-temperature performance of solid-state electrolytes remains a critical challenge. Herein, we present a facile and scalable approach for synthesizing a low-temperature-resilient polymer electrolyte based on ethylene-vinyl acetate, leveraging its unique molecular structure for enhanced lithium-ion transport. The ethylene-vinyl acetate polymer electrolyte (EPE) demonstrates a high ionic conductivity of 5.13×10⁻⁴ S cm⁻¹ at room temperature and retains a remarkable conductivity of 2.72×10⁻⁵ S cm⁻¹ at −40 °C. This superior performance is attributed to the synergistic interaction between the ester functional groups of ethylene-vinyl acetate and lithium salts, which reduces the ion dissociation energy barrier and facilitates efficient ion migration. The EPE enables stable lithium plating/stripping cycling for over 3000 h at −40 °C and supports the long-term cycling of LiFePO₄-based full cells at −40 °C for over 900 cycles. This work highlights the potential of cost-effective, scalable EPEs for next-generation solid-state lithium batteries, particularly in extreme environmental conditions.

The exploration and utilization of marine resources demand advanced operational tools. At present, deep-sea vehicles equipped with manipulators serve as the primary platforms for underwater exploration. However, the pressure sensors responsible for detecting the subtle gripping forces of these manipulators still face significant technical challenges, primarily due to the extreme hydrostatic pressure, corrosive seawater environment, and stringent mechanical strength requirements. A dual-curing, waterproof digital light processing (DLP) resin has been developed to achieve micron-scale printing accuracy, excellent seawater resistance, and mechanical properties comparable to those of thermoplastic resins. More importantly, the deep-sea pressure sensor (DSPS) features a unique printed lattice structure that allows seawater to penetrate and equilibrate the internal and external pressures, effectively mitigating the effects of deep-sea hydrostatic pressure. Experimental results demonstrate that the sensor exhibits a wide detection range and high sensitivity, with a measured sensitivity of 0.77 kPa⁻¹ under 30 MPa hydrostatic pressure and a signal fluctuation below 1.48%. Furthermore, both the sensitivity and detection range of the sensor can be tuned by adjusting the lattice parameters, providing a robust foundation for the advancement of marine resource exploration.

Virtual reality (VR) technology holds significant application values in entertainment, telemedicine, and other fields. However, current VR systems primarily reproduce visual and auditory stimulation with limited tactile feedback, while research on olfactory and gustatory reproduction remains relatively scarce. Given that olfaction plays vital roles in influencing human emotions, memory, and danger warning compared to taste, its absence significantly limits the multisensory immersive experience in VR applications; therefore, the development of olfactory display technology is crucial and essential nowadays. This paper categorizes reported olfactory display mechanisms into three types: airflow-based, atomization-based, and heating-based approaches, detailing their respective implementation methods and electrical characteristics. Furthermore, we systematically review the structural configurations and operational mechanisms of stationary, portable, and wearable olfactory display systems, while also examining recent advances in noninvasive electrical stimulation for inducing olfactory perception. Finally, driven by user demands for improved mobility and wearability in current wearable devices, along with advancements in flexible electronics, micro-electromechanical systems (MEMS), and artificial intelligence (AI), olfactory display technology is evolving toward flexible, wearable, miniaturized, and intelligent solutions.

Photoelectrocatalytic processes for detoxifying ofloxacin in hyposaline wastewater encounter significant challenges, primarily stemming from a weak built-in electric field (IEF) that causes inefficient separation of photogenerated carriers, coupled with low reaction activity. In this work, we introduce a crystal dipole engineering strategy that leverages high-valence Mo-BiVO₄ to enhance both photoelectrocatalytic activity and detoxification efficiency, as demonstrated by the improved performance of BiVO₄ in degrading ofloxacin. Mo atoms are incorporated into the BiVO₄ lattice to break the symmetry, significantly enhancing the crystal dipole moment. This augmentation intensifies IEF within BiVO₄, thereby promoting directional carrier migration. Optimized IEF reached 2.05 times that of pristine BiVO₄. Mo-doped BiVO₄ photoanodes exhibit remarkable enhancement in electron-hole separation efficiency, playing a pivotal role in photoelectrocatalytic applications. Remarkably, 4% Mo-BiVO₄ achieved 96.5% ofloxacin degradation within 60 min. Remarkably, it maintains 91.9% degradation efficiency in natural lake water containing saline and organic interferents, high-lighting its exceptional anti-interference capability. This work elucidates a strategy for boosting photocatalytic performance through unit-cell dipole engineering and enhanced IEF, aiming to enhance the sustainability of wastewater treatment processes.

Ionogels, with their combined properties of flexibility, excellent ionic conductivity, and biomechanical characteristics similar to biological tissues, have become key materials in flexible electronics, exhibiting enormous application potential in fields such as health monitoring and smart wearables. However, ionogels are susceptible to mechanical damage. Under large deformations and continuous mechanical loading, structural damage and device failure are inevitable. Self-healing ability can significantly improve the reliability, service life, and safety of devices. This review discusses the latest progress in self-healing ionogels, covering self-healing mechanisms, as well as the design, preparation, and applications of various ionogel-based flexible electronic devices, including wearable sensors, flexible triboelectric nanogenerators, supercapacitors, flexible displays, and soft robots. Furthermore, based on the self-healing mechanisms of ionogels and the design and manufacturing of related products, we put forward perspectives on the development of flexible electronics. This review is expected to accelerate the development of self-healing ionogels in the applications of various flexible electronic devices.